US reports breakthrough in methane hydrates gas production

02 May 2012 18:35[Source: ICIS news]

WASHINGTON (ICIS)--ConocoPhillips and a Japanese company have completed a successful and unprecedented demonstration of sustained natural gas production from methane hydrate deposits in ?xml:namespace>Alaska, the Department of Energy (DOE) said on Wednesday.

The department said that ConocoPhillips and the Japan Oil, Gas and Metals National Corporation (JOGMEC) achieved a steady flow of natural gas production over a 30-day period from a methane hydrates field in the North Slope of Alaska.

The previous duration production test of natural gas output from hydrates ran for only six days in 2008.

“While this is just the beginning, this research could potentially yield significant new supplies of natural gas,” said Energy Department Secretary Stephen Chu.

He said that based on the hydrates production test that was concluded on 10 April, the department plans to spend some $11.5m (€8.74m) this year and next on additional field work “to conduct a long-term production test in the Arctic as well as research to test additional technologies”.

Those additional production technologies, along with the technique used on the North Slope in last month’s test, “could be used to locate, characterise and safely extract methane hydrates on a larger scale in the US Gulf Coast”, the department said.

Methane hydrates – also known as natural gas hydrates or just gas hydrates – consist of an open, solid lattice of water molecules that enclose, without chemical bonding, molecules of methane.

Gas hydrates are stable at varying levels of pressure and temperature, even up to 50° Fahrenheit (10° Celsius), although generally they are found at low but not necessarily freezing temperatures.

When heated or removed from their usually high-pressure environments, the hydrates release methane, the principal component of natural gas.

The 30-day North Slope demonstration production completed last month used a process in which carbon dioxide (CO2) and nitrogen are injected into a hydrates deposit, lowering pressure in the formation, freeing methane and replacing it with CO2.

The process, said DOE, has the added benefit of sequestering CO2.

Although no one really knows how much gas might reside in methane hydrates, a 2009 study by the US Congressional Research Service (CRS) estimated that the US has as much as 320,000,000bn cubic feet (bcf) (or 320 quadrillion cubic feet) of gas-bearing hydrates in onshore and offshore deposits.

The US consumes about 23,000 bcf of natural gas annually.If even a fraction of methane hydrate resources can be commercially developed, they could supply US natgas needs for centuries.

ConocoPhillips said that the North Slope test production run of last month “is an important step in developing production technology to access this potential resource while sequestering carbon dioxide”.

The department said that the next step would be to evaluate gas hydrate production over longer durations, “with the eventual goal of making sustained production economically viable”.

While that goal may take years to accomplish, said Chu, “the same could be said of the early shale gas research and demonstration efforts that the department backed in the 1970s and 1980s”.